Fuel oil pump units are used to pump fuel oil to oil burning furnaces for heating residential and commercial buildings. By virtue of the application and where furnaces are located, fuel oil pump units often are required to fit a small confined area of a predetermined package size. Examples of fuel oil pump units are disclosed in U.S. Pat. Nos. 3,360,190; 3,446,230; 3,446,231; 3,446,232; 3,566,901; 4,021,155; 4,171,939; 4,255,093; 4,391,580; 4,685,871; 4,728,271; 4,856,553; 4,858,884; 4,898,523; 4,958,997; 5,145,328; 5,316,457; 5,346,174; and 5,692,680, and application Ser. Nos. 10/017,153 and 10/115,742, all assigned to the present assignee, and all of which are hereby incorporated by reference in their entireties.
As disclosed in these patents and patent applications, the basic structural design for an oil pump unit typically comprises a pump body often formed of cast iron and a pump cover often formed of aluminum. The pump body typically contains a crescent type gear pump that pumps fuel oil from a local reservoir (defined between the pump body and pump cover) that is supplied oil from a fuel oil storage tank. The pump unit also comprises a fuel regulator that is adapted to regulate flow of fuel oil from the gear pump to a nozzle outlet passage. The nozzle outlet passage is adapted to be connected to the combustion chamber of a furnace.
To a large extent, this basic structural design has remained the same and has provided excellent reliability, low cost and other desirable characteristics. The present assignee, Suntec® Industries, has manufactured and continues to manufacture a number of different commercially successful models of oil pump units incorporating this basic structural design.
Many years ago, most oil pump units had a mechanically actuated fuel regulator (e.g. such as a pressure sensitive diaphragm valve which is used to control the opening and closing of the regulator). However, many of the more modern designs (which have retained the basic structural design of mechanically controlled regulators) now incorporate electronic control of the regulator, such as may be provided an electrically actuated solenoid valve. As a result of this trend, many current Suntec® models of fuel oil pump units now incorporate a solenoid valve. The solenoid valve is typically mounted on the top side of the pump body which is often the most convenient location to provide for control over the fuel regulator. Because solenoid control based designs have been in existence for a number of years, there is a large number of existing Suntec® oil pump units having solenoid valve control that are currently employed in the field.
As will be readily appreciated by maintenance and service technicians in the industry, oil pump units must be replaced or repaired from time to time due to normal wear and usage. Because existing applications need to be serviced and replaced from time to time, any design changes to an existing model of an oil pump unit typically require a pump unit configuration with about the same package size in order to properly fit into the available space for existing applications. Also, the oil pump unit must typically provide the same port configuration to provide for ready connection to the existing furnace and supply line plumbing.
The next future trend in the fuel oil heating industry will likely be to provide smart feedback to oil pump unit and furnace systems. Sensors may be employed to monitor various burner parameters such as pressures, temperatures and flame brightness. From this feedback, it can be determined if the oil pump unit is operating properly. The data will be transmittable to remote locations (e.g. via phone lines) for remote monitoring by service technicians who normally service and maintain oil pumps units and associated furnaces. To accommodate this trend, systems will need to incorporate a pressure sensor and a vacuum sensor.
Some models of oil pump units already have two inlet side ports upstream of the gear pump and two outlet ports downstream of the gear pump. With extra ports already provided in this configuration, these models of oil pump units can readily accommodate a vacuum sensor on the inlet side and a pressure sensor on the outlet side. However, many models of oil pump units do not provide an extra outlet side port to accommodate a pressure sensor. This presents a problem since as discussed above, the existing package size, design and port configuration can not readily be changed due to the need to accommodate existing applications, which often require a given package size and port configuration.
One solution conceived by the present inventor is to provide an additional outlet pressure port along the top side of the pump body to accommodate a pressure sensor. This may provide a solution for oil pump models that are mechanically controlled solely through diaphragm valves (i.e. models without solenoid valves). However, in solenoid valve type models, the solenoid valve is typically mounted to the top side of the pump body. Therefore, in designs incorporating solenoid valves such as Suntec® model nos. A2EA-6520, A2VA-3006 and A2VA-5006, there is not room to provide an additional port to receive a pressure sensor along the top side of the pump body. A potential and previously unknown solution to this issue which has been conceived by the present inventor is to provide an external connection in the plumbing such as providing a t-section in the external copper tubing that connects to the single nozzle outlet provided by oil pump unit. However, this location is somewhat inaccessible when the burner is mounted to the appliance (boiler or furnace). This also would increase the cost and number of parts for oil burner systems.